Method for making a multi-ply continuous filament ballistic helmet

Abstract

Method for making a laminated ballistic helmet from plural, continuous filament resin-coated layers. A continuous filament bundle, yarn or end is deposited on a plurality of different sized helmet-shaped preforms. A resin is coated upon or impregnated into the continuous filament bundle, yarn or end, either before or after deposition. The resulting resin containing preforms are stacked in nested relation and then molded to produce a bonded, laminated ballistic helmet.

What we claim and desire to secure by Letters Patent of the United States is: 
     
       1. A method for making a ballistic helmet, comprising the steps of: (1) forming plural nestable, helmet-shaped, resin containing preforms, each being made by depositing at least one continuous filament bundle on a helmet-shaped form, coating the continuous filament material with a solvent solution of curable resin and removing the solvent from said solution;   (2) only partially curing the resin;   (3) then arranging the preforms in nesting relation in a mold to form a stack of partially cured preforms; and,   (4) applying heat and pressure to bond said stack of partially cured preforms together by further curing the partially cured resin in the preforms, thereby molding said stack of partially cured preforms into a laminated helmet.   
     
     
       2. The method of claim 1, wherein said plural preforms are produced by depositing a continuous filament bundle onto a plurality of different sized, helmet-shaped forms 
     
     
       3. The method of claim 2, wherein said continuous filament bundle is deposited by blowing it onto the helmet-shaped forms. 
     
     
       4. The method of claim 3, wherein said helmet-shaped forms are porous screens and further comprising the step of applying a suction to the inside of each helmet-shaped porous screen when the continuous filament bundle is blown thereon to temporarily hold the bundle on the screen. 
     
     
       5. The method of claim 4, wherein the continuous filament bundle is blown onto the helmet-shaped forms by entraining the continuous filament bundle in a moving stream of a gas. 
     
     
       6. The method of claim 1, wherein said plural preforms are produced by depositing a continuous filament yarn onto a plurality of different sized, helmet-shaped forms. 
     
     
       7. The method of claim 1, wherein said plural preforms are produced by depositing a continuous filament end onto a plurality of different sized, helmet-shaped forms. 
     
     
       8. The method of claim 1, wherein the resin content of the coated continuous filament bundle is in the range of 20 to 30 percent by weight. 
     
     
       9. The method of claim 1, further comprising the step of precompressing the stack of nested, partially cured preforms before molding. 
     
     
       10. The method of claim 1 wherein said continuous filament material is an aramid fiber. 
     
     
       11. The method of claim 1 further comprising the step of depositing a predetermined quantity of said at least one continuous filament bundle onto the helmet-shaped form. 
     
     
       12. A method for making a ballistic helmet comprising the steps of: (1) forming plural, nestable, helmet-shaped, resin-containing preforms, each being made by: a. depositing on each one of a plurality of different sized, helmet-shaped forms at least one continuous filament bundle;   b. coating the continuous filament material of the bundle with a solvent solution of a curable resin after the continous filament bundle is deposited onto the helmet-shaped forms and,   c. removing the solvent from said solution;     (2) partially curing the resin;   (3) arranging subsequently the preforms in nesting relation in a mold to form a stack of partially cured preforms; and,   (4) applying heat and pressure to bond said stack of partially cured preforms together by further curing the partially cured resin in the preforms thereby molding the stack of partially cured preforms into a laminated helmet.   
     
     
       13. The method of claim 12, further comprising the steps of exposing the resin coated continuous filament bundle to a flow of a heated gas to remove the solvent by evaporation and to advance the cure of the resin before stacking the preforms in the nested relation. 
     
     
       14. The method of claim 12, further comprising the step of reducing the flow of the resin to the molding consistency before arranging the preforms in the nested relation. 
     
     
       15. The method of claim 14, further comprising the step of exposing the resin coated continuous filament bundle to a flow of a heated gas. 
     
     
       16. The method of claim 14, wherein the resin content of the coated continuous filament bundle is in the range of 20 to 30 percent by weight. 
     
     
       17. A method for making a ballistic helmet comprising the steps of: (1) forming plural, nestable, helmet-shaped, resin-containing preforms, each being made by: a. depositing on each one of a plurality of different sized, helmet-shaped forms at least one continuous filament;   b. coating the continuous filament material of the bundle with a solvent solution of a curable resin before the continuous filament bundle is deposited onto the helmet-shaped forms and,   c. removing the solvent from said solution;     (3) arranging subsequently the preforms in nesting relation in a mold to form a stack of partially cured preforms; and,   (4) applying heat and pressure to bond said stack of partially cured preforms together by further curing the partially cured resin in the preforms thereby molding the stack of partially cured preforms into a laminated helmet.   
     
     
       18. A method for making a ballistic helmet comprising the steps of: (1) forming plural, nestable helmet-shaped, resin-containing preforms, each being made by: a. depositing on each one of a plurality of different sized, helmet-shaped forms at least one continuous filament bundle,   b. impregnating the continuous filament material of the bundle with a solvent solution of a curable resin after the bundle is deposited onto the helmet-shaped forms and,   c. removing the solvent from said solution;     (2) partially curing the resin;   (3) arranging subsequently the preforms in nesting relation in a mold to form a stack of partially cured preforms; and,   (4) applying heat and pressure to bond said stack of partially cured preforms together by further curing the partially cured resin in the preforms thereby molding the stack of partially cured preforms into a laminated helmet.   
     
     
       19. A method for making a ballistic helmet comprising the steps of: (1) forming plural, nestable, helmet-shaped, resin-containing preforms, each being made by: a. depositing on each one of a plurality of different sized, helmet-shaped forms at least one continuous filament bundle,   b. impregnating the continuous filament material of the bundle with a solvent solution of a curable resin before the bundle is deposited onto the helmet-shaped forms and,   c. removing the solvent from said solution;     (2) partially curing the resin;   (3) arranging subsequently the preforms in nesting relation in a mold to form a stack of partially cured preforms; and   (4) applying heat and pressure to bond said stack of partially cured preforms together by further curing the partially cured resin in the preforms thereby molding the stack of partially cured preforms into a laminated helmet.   
     
     
       20. The method of claim 19 further comprising the steps of exposing the resin impregnated continuous filament bundle to a flow of a heated gas to remove the solvent by evaporation and to advance the cure of the resin before arranging the preforms in the nested relation.